Multiphase LLC DC-Link Converter with Current Equalization Based on CM Voltage-Controlled Capacitor

Yue-Lin Lee and Kuo-Ing Hwu ()
Additional contact information
Yue-Lin Lee: Delta Electronics Inc., No. 186, Ruiguang Rd., Neihu Dist., Taipei City 114501, Taiwan
Kuo-Ing Hwu: Department of Electrical Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan

Energies, 2024, vol. 17, issue 11, 1-27

Abstract: In this study, a current-equalization technology utilizing a variable-capacitance technique for a multiphase inductor–inductor–capacitor (LLC) converter is studied. Accordingly, the proposed method involves adjusting the resonant capacitance of the LLC resonant converter to balance the currents between phases. This is achieved primarily by biasing ferroelectric multilayer ceramic capacitors (MLCCs) through a step-down circuit and a common-mode bias structure. These ferroelectric MLCCs serve as the resonant elements, allowing for variable capacitance by leveraging capacitance sensitivity to their trans voltages. This approach provides additional control flexibility to the resonant circuit. Furthermore, since each phase operates independently, the circuit can be scaled to accommodate any number of phases. Moreover, all switches in the circuit have zero-voltage switching (ZVS) turn-on, minimizing switching losses. This study initially analyzes and evaluates the proposed common-mode bias variable capacitance technique and the corresponding operational principles. Subsequently, a two-phase LLC experimental circuit based on a field-programmable gate array (FPGA) digital controller is utilized to assess current equalization and efficiency. That is to say, this experimentation aims to validate the effectiveness of the current-equalization variable-capacitance technique in an LLC resonant converter.

Keywords: common-mode bias structure; current error ratio; efficiency; ferroelectric MLCC; variable capacitor; LLC resonant converter; multiphase converter; current equalization; FPGA controller (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2024
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/17/11/2793/pdf (application/pdf)
https://www.mdpi.com/1996-1073/17/11/2793/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:17:y:2024:i:11:p:2793-:d:1410161

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().